Biologists are engineering sophisticated kill switches that prevent genetically modified microbes that have been designed to cure diseases or clean up oil spills from going rogue. For instance, scientists at Harvard and Yale have developed a switch called Deadman that forces the engineered microbe to rely on lab-made molecules that do not exist in nature. Another kill switch called Passcode keeps microbes in check by forcing them to adhere to a pre-set combination of molecules. The work was described in a recent study in Nature Chemical Biology.

Optogenetics, the combination of genetics and optics to control well-defined events within cells of living tissue, is a hot topic in neuroscience right now. But a recent animal study appearing in Nature this week suggests that manipulating brain circuits with light and drugs can cause ripple effects that could muddy experimental results. Working with rats and zebra finches, a team of scientists from Harvard found that stimulating one part of the brain to induce certain behaviors might cause other, unrelated parts, to fire simultaneously, and so make it seem as if these circuits are involved in the behavior.

A transgenic chicken approved by the US Food and Drug Administration is producing a drug in its eggs that can be used to treat a rare inherited condition that prevents the body from breaking down fatty molecules in cells. The disease that the drug, Kanuma, is designed to treat, lysosomal acid lipase deficiency, causes fat to accumulate in the liver, spleen and vasculature. A form of the disease that strikes infants is quickly fatal. A second form that affects older patients causes liver enlargement, fibrosis and cirrhosis, as well as cardiovascular disease. Kanuma is just the third in a small group of “farmaceuticals” and the first drug produced in chickens.